Stator for an axial flux electrical machine

Abstract

The present invention provides an improved stator for an axial flux electrical machine in which the stator discs which contain the windings of the stator are spaced apart by spot spacers to provide improved quantity and control of the cooling fluids passing though the stator. The present invention further provides improved control of the flow of cooling fluids through the stator by controlling the points at which the cooling fluid enters and exits the space between the stator discs.

1 . A stator ( 2 ) for an axial flux electrical machine, the stator having one or more stator disc units ( 21 ) comprising: 
 a plurality of stator discs ( 22 ) having a plurality of spot spacers ( 1 ) therebetween.    
     
     
         2 . A stator according to  claim 1 , wherein the spot spacers are circular.  
     
     
         3 . A stator according to  claim 1 , wherein the spot spacers are tear-drop shaped.  
     
     
         4 . A stator according to  claim 1 , wherein the spot spacers are generally rectangular.  
     
     
         5 . A stator according to any one of the preceding claims, wherein the spacers are uniformly arranged around the axis of the stator disc.  
     
     
         6 . A stator according to  claim 5 , wherein the spacers are arranged in radially extending rows.  
     
     
         7 . A stator according to  claim 6 , wherein the adjacent rows of spacers are radially offset.  
     
     
         8 . A stator according to any one of  claims 1  to  4  wherein the spacers are irregularly arranged.  
     
     
         9 . A stator according to  claim 8 , wherein the concentration of spacers in a given area is selected according to the desired flow of cooling fluid in that area.  
     
     
         10 . A stator according to  claim 9 , wherein the desired flow of cooling fluid is selected according to the path length of the cooling fluid through the space between the stator discs.  
     
     
         11 . A stator according to any one of the preceding claims, wherein each stator disc unit also comprises one or more additional spacers ( 100 ), having a different shape to the spot spacers ( 1 ), between said stator discs.  
     
     
         12 . An axial flux electrical machine comprising a stator according to any one of the preceding claims.  
     
     
         13 . An axial flux electrical machine comprising: 
 a rotor ( 30 ) having one or more rotor discs ( 31 ), and a stator ( 2 ) having one or more stator disc units ( 21 ), each stator disc unit comprising a plurality of stator discs ( 22 ), wherein 
 a cooling fluid passageway is defined which includes a portion which passes through the or each space between the stator discs, and a further portion which passes between the stator disc unit ( 21 ) and the or each adjacent rotor disc ( 31 ).  
   
     
     
         14 . An axial flux electrical machine comprising: 
 a rotor ( 30 ) having one or more rotor discs ( 31 ), and a stator ( 2 ) having one or more stator disc units ( 21 ), each stator disc unit comprising a plurality of stator discs ( 22 ), having: 
 a first cooling fluid passageway which includes a first portion which passes from a hollow interior of the rotor ( 30 ), radially through one or more passages in the rotor into the space between the inner circumference of the stator disc unit and the or each rotor and a second portion which passes between the stator disc unit ( 21 ) and the or each adjacent rotor disc ( 31 ); and  
 a second cooling fluid passageway lying between adjacent stator discs and having at one or more inlets and one or more outlets on the circumference of the stator disc unit, such that, in use, cooling fluid enters the second cooling fluid passageway through an inlet and out again through an outlet.  
   
     
     
         15 . A machine according to  claim 14 , wherein the stator disc unit has a single inlet and a single outlet arranged circumferentially on opposite halves of the stator disc unit.  
     
     
         16 . A machine according to  claim 14 , wherein the stator disc unit comprises a plurality of inlets and a plurality of outlets which are regularly arranged around the circumference of the stator disc unit with each inlet or outlet being arranged between a pair of adjacent outlets or inlets respectively.  
     
     
         17 . A stator for an electrical machine, substantially as described herein with reference to the accompanying drawings.  
     
     
         18 . An axial electrical machine substantially as described herein with reference to the accompanying drawings.